


How to Build A Snowman

by Deburine



Category: Vocaloid
Genre: Belly Kink, Button Popping, F/M, Fluff, Rapid expansion, Rapid weight gain, Weight Gain, fat kink, magical weight gain
Language: English
Status: Completed
Published: 2021-01-27
Updated: 2021-01-27
Packaged: 2021-03-13 08:55:31
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,105
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29026089
Author URL: https://archiveofourown.org/users/Deburine/pseuds/Deburine
Summary: Kaito is a snow sprite excited to show his crush, the spring fairy Miku, what the first day of winter is like. But when one of his spells misfires, he finds himself with a heavy problem to solve - and a date to save!(Mature because of the kink, there's no smut)
Relationships: Hatsune Miku/Kaito
Kudos: 17





	How to Build A Snowman

As the winter winds chilled the sleepy mountain village, every child was filled with anticipation for just one thing. The first winter snow. Every morning the show would awaken hoping to see a sea of white, and they would go to sleep praying for the touch of the "snow sprites."  
  
And this year, one such snow sprite was eager to do his part. A pale blue haired lad named Kaito. Indeed, while the people of the village believed the snow sprites were merely a fun legend for the children, they were quite real... but invisible and untouchable by humans.  
  
Not that they kept to themselves. Kaito, like all of his kind, helped create and tame the snow during winter. And there was nothing Kaito loved more than that first snow fall, as the children rushed into the white fluff and played. He often dearly wished he could join them himself, but he _was_ a spirit creature. So instead he would take pride in helping his kin with their work in making that experience special.  
  
But this year he had another reason to look forward to the snow. Kaito had started to mature as a sprite and this year he'd finally started to learn how to channel his own spirit into creating snow himself. Oh, there had certainly been some mishaps - his enthusiasm often led to consequences with his magic misfiring and creating all sorts of difficult circumstances, usually with himself as the unfortunate victim. But he was certainly confident that he was ready to show off his potential without mistakes!  
  
And how dearly he wanted to impress someone this year... For just as the snow spirits aided in the spread of winter, there were spirits that governed other seasons as well. And this spring he'd met a particularly captivating flower fairy.  
  
Her name was Miku, and her hair and clothes were as pink as the cherry blossoms she allowed to bloom. Just as much as Kaito loved to spread joy through the delicate snowfall, Miku loved nothing more than to create cascades of color through the blossoms in the trees.  
  
It wasn't easy for them to see each other - nature itself tended to keep their work separated. Kaito tried to see her as much as possible anyway, and he couldn't help but develop a dopey crush on her that his colleagues playfully teased him over. And the last time they'd met, he'd worked up the courage to ask Miku to come see the wintertime paradise he would build in his little part of the town. If he couldn't quite get what he wanted to express across in words, surely he could do it with magic, right?  
  
"Brrr... its so chilly..."  
  
Kaito's smile broadened as he turned to see Miku emerging from the ether, fading in just near a bare tree. "Hee hee, I don't know how you handle this! Are you sure you're bundled up enough?"  
  
To Kaito's surprise, there stood Miku in her normal spring clothes, her pink school girl's uniform with flower prints and her tall pink boots. She shivered a moment as she clutched at her shoulders, her pink sleevelets ruffling from the winter breeze. To Kaito, she looked positively radiant, a bright being of color against a cold and mono-colored world. "Well I did bring my jacket," Kaito said with a laugh, gesturing to his long white coat with the asymetrical black half-coat on the right side. His buttoned up shirt loosely hung over his long white pants and fancy shoes.  
  
Kaito straightened his blue tie as he stared out at the autumn field, the bare trees, and small pond. Miku took a seat under the tree.   
  
'Time to show her what I'm made of!'  
  
Delicately he traced his hands through the air, causing white wisps of frost to flow forth. He felt the magic channeling through his body - ironically, it felt warm despite his chilly creations. He lightly tossed the frost towards the tree Miku sat underneath, watching it cling delicately to the branches as he allowed it to build up giving the tree a delicate white glow. Miku smiled at him and Kaito starting feeling a little more cocky.  
  
"Heh, that's simple! Now for the REAL deal!"  
  
Kaito drew more power out of his body and scattered vast quantities of snow across the grass in a great white sheet. He leapt into the air, somersaulting as he tossed great piles of it around him. And he landed atop it with a light crunch, his airy feet leaving no mark for humans to find. He took a few breaths to center himself - the mistakes always happened when he overdid it. "Oh wow, I didn't you could be so acrobatic!" Miku said with a laugh.  
  
Kaito's smile broadened as he winked at her, rushing through the sheet of white and allowing great clouds of frost to burst from his finger tips and coat the remaining trees. He dove through the air towards the lake, spinning around as he drew up as much magic as he could... he could feel light painful pricks as he did so, letting him know he was at his limit...  
  
Before he plunged into the water, he threw out a great wall of frost and ice, turning the tranquil water into a solid layer of perfect skating ice. Kaito landed lightly on the cold surface and took a bow, trying to cover up how tired he was.  
  
"OH WOW! THAT WAS SOOOOOOO COOOOOOL!"  
  
Kaito glanced up and saw that Miku was _not_ his only audience anymore. For there in the center of the snowy field stood a little brown-haired pig-tailed girl in a red jacket and ruffled skirt, black striped tights, and a thick pink scarf. She clapped her pink-mittened hands together in excitement. "A snow fairy, a snow fairy! I got to see a snow fairy!"  
  
The blue haired snow _sprite_ straightened out and put a hand behind his head in embarrassment as he watched Miku clap for him as well. Kaito knew the human child wasn't able to see him, only the magic he'd performed, but he found himself wanting to do something for her as well as for Miku. He gently slid across the ice to the snow-coated shore, close to where the little girl was standing. 'Something nice for a kid... hmmm... I know!'  
  
He waved his hands through the snow, causing it to dance as the girl stopped clapping, her eyes growing wide. Kaito winced briefly as he felt a sharp pain cut through him, but he pushed himself just a little more... surely what he had in mind wouldn't cause any misfires, right? The snow swirled around into two round snowballs, forming a short little snowman roughly the height of his intended audience. Kaito thought he felt something strange happening as he finished the spell... as if a part of himself had been cut off and drifted away... he clenched his teeth as he tried to conceal that brief moment of pain lest Miku's wonder be replaced by worry.  
  
"Thank... thank you Snow Fairy!" the girl said with a cheer, leaning forward and hugging the snowman.  
  
"I guess that's all I'm getting for a hug..." Kaito said with a forced laugh as he stood up, a little dizzy from so much use of his power.  
  
To Kaito's surprise, Miku stood up and skipped over to him, wrapping her arms around him in a great hug for him. "Thanks for the show, Mr. 'Snow Fairy,'" she giggled, "I never get to enjoy winter..."  
  
Kaito's face blushed red as he lightly put his arms around her as well. "Um... Miku... w-would you..."  
  
He cleared his throat, trying to sound more confident, "How would you like to join me on the ice?"  
  
Miku's glowing smiles could easily thaw any great winter. "I would love to!"  
  
As the two broke from their hug, Kaito felt a warm rush as Miku held his hand while they left for the ice. He just barely heard the human girl scampering around and gathering ever more snow, but thought little of it at the time.  
  
To Kaito's relief, his weakness healed as he and Miku lightly slid along the ice without skates - being spirits, they were such delicate creatures that they needn't worry about using tools to help them. As his energy came back, he started to find himself showing off again on the ice, doing ever more elaborate acts of figure skating. Miku seemed to want to match him, gliding along through the air as Kaito couldn't help but marvel at how lovely Miku looked when she spun through the air encircled by her pink twintails, like a delicate cocoon. But he wanted to impress her, and he kept pushing himself harder, trying to keep leaping and twirling in ever more impossible-seeming ways.  
  
After delicately landing from a triple-rotation spin, Kaito finally worked up enough courage to talk to her again. "Y... you know, Miku... now that I've shown you winter... Maybe you can show me spring too?"  
  
Miku winked at him. "Oh, I would love to!" she said, "There's so much to do! Once the flowers bloom, we always serve a great feast! There's so many sweets too..."  
  
"Sweets?!"  
  
Kaito lit up on hearing that as he started skating backwards. For a moment, he thought he felt some pressure around his waist, but he ignored it as he watched Miku start twirling around in circles. "What kind of sweets do you serve in the spring!? We snow sprites love to have ice cream this time of year, plus all that nice Christmas cake, peppermint... gingerbread men..."  
  
Oh, Kaito couldn't wait to enjoy a nice sugary meal when he return to his home...  
  
Miku smiled as she started to explain her own traditions. "Oh, tarts and cookies and syrupy lollipops... Cupcakes with colorful frosting... We always use bright sugary syrups that make us think of flowers opening up! I always try to make something new every year!"  
  
It sounded so heavenly! And Miku baked?! He never knew... Kaito thought for a second that he'd seen Miku blush as her smile grew softer. "I... I would love to have you share it with me... Kaito. I'll even make something special just for you."  
  
Kaito's goofy smile spread and he went to take another leap through the air... but felt an odd wobble as his center of gravity shifted, as if there was more weight around his middle than he was expecting. He managed to correct himself but came to a rough landing, hardly graceful at all. 'Ugh... I need to pay more attention...' he thought to himself, 'I've never made a goof like that though...'  
  
He started to speed forward again, but he was starting to notice he needed more force to build up his momentum again - was he just getting tired? That had to be it, right? It wasn't as if he'd spontaneously gotten heavier! But as he pressed forward, he thought he felt a tightening feeling along the waist of his pants... he tried to jump one more time to ignore it...  
  
... only to completely fail to lift himself through the air as that weight dragged him down, causing him flounder around and land right on his butt on the ice.  
  
"Oh! Kaito, are you okay?!"  
  
Miku skated over to him as Kaito grumbled, trying to push himself up and now he _really_ noticed that he felt heavier. He looked down at himself and gasped at a most unusual sight. His normally flat middle had rounded out in front of him, pushing over his pants and pushing _out_ his previously loose shirt. He gingerly reached out with his bare fingers and touched it, pressing in just a little as he registered how soft it was. It was _real!_ But where had it come from?!  
  
He heard Miku approaching and tried to hunch over and use his jacket to hide his suddenly flabbier tummy... he didn't want her to see _this_! "Oh, I... I'm fine!" he stammered nervously, "I... I... I... probably just took that jump too fast!"  
  
"Well, at least let me help you up..."  
  
Kaito so wanted to take Miku's hand again but he was afraid of her seeing his stomach... how had this even happened?! He tried to turn around on the ice and finally managed to push himself up so Miku was only seeing the back of him... when he finally noticed that same tightness around his waistband spreading around the rest of his clothes. He glanced at his sleeves and saw his arms were growing plump... looking down he saw his pants starting to stretch around two thickening thighs...  
  
And his stomach, no, his _belly_ , was only getting larger and heavier...  
  
In a panic, Kaito started trying to skate away from Miku without any real plan of what he was going to do, feeling disgusted as his belly was finally large enough he could feel it shifting and bouncing as the rolls of fat only continued to pile on. It wasn't like he had anywhere to _hide_ from Miku, and he was mortified at the idea of returning to his fellow snow sprites looking like this! But he didn't even know why he was getting _fat_ let alone all at once! He'd need an elder sprite to look him over... _again_... After yet another embarrassing mishap...  
  
Kaito found his balance on the ice was getting hard to maintain with his rapidly increasing weight and he found himself slipping and falling again... he heard an embarrassing ripping sound from the back of his pants as his wide butt caused them to split up...  
  
It didn't take Miku long to catch up to him, her face filled with worry as she skated right in front of him. "Kaito, what's wrong, what's... oh... oh my..."  
  
Kaito tried to swallow a lump of embarrassment in his throat as he watched Miku take in his appearance - spread out on the ice with his fatter legs in front of him, his belly jutting out before him as it started to crush his belt and hang out under his shirt. "I don't know what's happening!" he said quickly, "It only just started a few minutes ago!"  
  
"And it doesn't look like it's _stopping_ either..." Miku murmured as her eyes stayed on his belly, seemingly mesmerized by its sudden size.  
  
Indeed, Kaito could only helplessly watch himself growing plumper. Though his belly seemed to be taking the most obvious growth, he could feel more weight piling on to the rest of him too, his bountiful butt spreading out behind him, his hips widening up... He could even see from his reflection on the ice that his face was getting softer as a roll of fat began to form around his chin...  
  
"Oh Miku... I think I messed up a spell again..."  
  
He felt so ashamed to admit it, but he could come up with no other conclusion. "I'm... I'm always screwing up my magic... Either I'm turning my hair into icicles, or exploding into a pile of snow... or... or... this..."  
  
He put a hand to his swelling belly and he could actually _feel_ it getting fatter, pressing his hand forward as it crept across his lap. Even his fingers were filling out as his hands started to puff up, the glove on his left hand starting to stretch up and cover even less of his pudgy wrists.  
  
"Kaito! This isn't the time to just stop and feel sorry for yourself!"  
  
Kaito snapped out of his malaise as he looked at Miku's determined face. "If you just messed up a spell, that means there's a way to turn you back, right? Think about what you were doing when you were casting all that magic and we'll work it out!"  
  
She was _right_ of course, it wasn't like this situation was irreversible... maybe Miku might be able to help him come up with a solution to his problem! Even if he hated the idea of burdening her with something so humiliating to him, if she already knew about it, there wasn't much point in leaving her out of it. Kaito crossed his arms as he tried to think, as well as trying to ignore the feeling of his breasts puffing up and starting to sag. "When I frosted the tree I felt fine... I didn't really started to feel 'off' until I was frosting the lake, that's the first time I noticed my magic was starting to strain me..."  
  
Miku reached out to help Kaito stand and his time he let her help him... while she still could, as by now he had to weigh over 300 pounds. He huffed and puffed as he made it back onto his feet, his stomach rolling out and forward as it stressed at the buttons of his shirt. He closed his eyes and mentally tried to search the lake for any kind of latent magic... but he felt nothing around him. It wasn't the lake that was somehow fattening him up.  
  
'So what else is left? The lake was the last spell...'  
  
"Kaito, what about the snowman?"  
  
Miku's words immediately made Kaito remember the searing pain he'd felt when he'd crafted that "simple" snowman. What if...  
  
"Okay, we'll go check on the snowman!" he said.  
  
Thank to his increasing obesity, Kaito was struggling to move foward on the ice, but Miku kept a tight grip on him and helped guide him to shore before he got heavy enough to break the ice underneath him. It was a much wider Kaito that left the lake, his bottom and hips having grown enough to start shrinking the amount of coverage his jacket was giving him. He felt his heavier footsteps sinking into the snow as he was forced to waddle forward, though his deeper footprints would still only be visible to his own kind and not to humans. As he and Miku finally made their way back to the snowman, he'd grown so fat his belly was swaying in front of him and straining his shirt buttons to their absolute limit. He could feel his pants clinging to his shaking thighs and worried about how much more abuse they could take, while his arms were completely filling out his jacket sleeves as they packed into the tightening fabric like soft dough. All the while Miku was silent... no doubt, she just wanted to help Kaito figure out his problem so she could leave this miserable outing behind her... and leave _Kaito_ behind as well after he'd proven to be such a screw up.  
  
'I... I just wanted to have a nice date with her... of course an idiot like me would ruin it...'  
  
When Kaito finally made it back to the meadow and laid eyes on his snowman, he knew _exactly_ what was happening to him.  
  
Kneeling in the snow was the human girl from before as she hummed a Christmas carol to herself. The snowman had now been given a face, arms, a bucket hat, and even a small scarf... but more worryingly for poor Kaito, the snowman was _far_ bulkier than when he'd created it before. And only getting "fatter" as the little girl kept rolling up ever more packs of snow to widen it up.  
  
"When I cast the spell to create the snowman... it felt like I'd broken myself somehow... and that part of me had disappeared..."  
  
Kaito waddled over to the snowman nervously and as he kept getting closer to it, he was finally able to sense the magical fragments inside of it. Parts of _himself._  
  
"Ohhh... I think I get it! Even if it was by accident, the snowman is basically a copy of you now... so when she keeps adding all that snow to the snowman..."  
  
"...it's adding weight to _me,"_ Kaito grumbled, folding his hands over his round stomach in annoyance.  
  
Miku let out a sigh of relief. "Well, that's easy then! You just have to get rid of the snowman and reclaim that bit of your soul and you'll go back to normal!"  
  
"That's... that's it, huh?"  
  
Kaito lifted his heavy arms up, his taut sleeves restricting his movement. One good strong gust of wind would blow the snowman apart and let him have his properly slim body back, right? He tried to carefully summon the winds... when the girl stopped singing her carol for a moment.  
  
"Oh, don't worry Mr. Snowman, I'll make sure you're big enough to hug... just like papa was..."  
  
Kaito swallowed another lump in his throat and lowered his arms. On seeing Kaito stop, Miku approached the snowman and held her hands out. "Here, I can probably summon up something warm to melt it and that will..."  
  
Without a word, one of Kaito's chubby hands wrapped gently but firmly around her outstretched wrist. He shook his head, causing his extra chins to wobble. "It's... it's not so bad, right?" he stammered, "It's going to be warm tomorrow... so the snowman will melt on its own... I'll be fine when that happens. She's really happy like this, I wouldn't want to ruin it... and... it's just a little weight, right?"  
  
Kaito's "little" belly finally burst free of his shirt with a great snapping sound as the buttons popped off, landing in the snow and leaving his flabby torso completely exposed. His moobs had softened and swelled into two great pillowy pads that drooped along his humongous belly that kept quivering with his every heavy movement, his belly button having grown deeper as it began to be swallowed up by the increasing flesh on his torso. Kaito heaved a great sigh and started to trudge away, feeling his fat thighs brush up against each other as a few seams started to come undone along the sides, his arms resting along the rolls built up along his sides and pushing them away from his body. At least _one_ of the people he'd tried to make happy would still _be_ happy.  
  
Suddenly Miku ran up in front of him. "Where are you going?" she asked.  
  
"Home... while I can still walk, anyway."  
  
Kaito tried to chuckle to stave off his embarrassment, but he suddenly worried that _maybe_ that was an actual concern...  
  
Miku stayed planted in front of him, her face unreadable. "So you're done showing me the winter?"  
  
Kaito blinked a few times in surprise. "You... you still _want_ me to?"  
  
Miku's face was turning as pink as her hair as she nodded. Kaito shook his belly for emphasis. "Even after I ruined it?"  
  
"You didn't ruin anything!" she said, "In fact..."  
  
Kaito released his belly as Miku approached him and gave him a huge hug, wrapping her arms around him as she slipped her hands under his coat and torn shirt, snuggling right into his flabby body as she tried to reach as far as she could around his widened form. "I never knew a snow sprite could be this warm..." she whispered, lightly caressing some of his fat folds along his sides, "But you are... your heart and your body..."  
  
Now _Kaito_ had a pink face. She liked him like this?! But he felt that goofy smile come back as he closed his chubby arms around her, completely enclosing Miku's upper body in a warm, chubby hug. "If I didn't know better, I'd think you just wanted to get some protection from the cold," he joked.  
  
Miku laughed and snuggled him even tighter, and he could actually feel her sinking deeper into his stomach and chest. Kaito's legs were starting to shake as he found himself getting tired from standing already - his body was _still_ fattening, still growing heavier, and starting to wear him out from just trying to keep it mobile. He slowly led Miku over to the frost covered tree and spread out under it, letting Miku stay cuddled up to his soft, swelling form. After all, snow didn't make _him_ cold, so he could sit in it for hours while she borrowed his extra warmth...  
  
Hours... with Miku in his arms...  
  
And so the two of them stayed like that, making some small talk and enjoying each other's company, all the while watching as the human girl with no inkling of her role in the events continued to build her monumentally fat snowman - and unknowingly plumpen up the equally fat but happy snow sprite. Eventually she noticed a small scattering of white buttons around her and laughed with joy as she stuck them on the snowman's torso, silently thanking the kind spirits of winter for giving her such a lovely gift.

**Author's Note:**

> I originally had the idea for this before Yuri on Ice came out. Then Yuri on Ice came out and I put in all these ice skating scenes. So this one is a few years old, but it's one that I still have a lot of affection for because the pairing is so sweet. A very innocent but klutzy Kaito and a very helpful, cheery Miku. I'll do a repost of the sequel when it's in season again ;)
> 
> The picture is of course by the great wintery Ghost Artist woooooo and the full size is still on my old [DeviantArt profile.](https://www.deviantart.com/debuchan/art/Do-you-want-to-fatten-a-snowman-649335954)


End file.
